Copper Lake

The LakeGrade rubric puts Copper Lake at a C: clarity at 7.0 ft, phosphorus readings still being added, and a TSI of 49 signal an intermediate trophic state.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. Copper Lake is unusually deep for Minnesota at 52 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake is compact at 37 acres, with 2.5 miles of shoreline and little volume to buffer nutrient inputs. Copper Lake sits at rank 78 of 128 in Cook County, in the lower half of the local distribution.

Copper Lake has no invasive species recorded in Minnesota state databases as of 2020, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Copper Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.